Proposed work will be on the activation mechanism of the glucocorticoid receptor of rat liver especially on the groups responsible for binding of the receptor to DNA. In addition the nature of the physiological role of binder IB will be sought. BIBLIOGRAPHIC REFERENCES: G. Litwack, Comparison of ligandin with a new (basic) binding protein, corticosteroid binder IB, of liver cytosol, in I.M. Arias and W.B. Jakoby (editors), Glutathione: Metabolism and Function, Raven Press, New York, pp. 285-299 (1976). J.A. Goidl, K.P. Dolan, M.H. Cake, L.G. Parchman and G. Litwack, Reversible activation of the glucocorticoid receptor, Fed. Proc. 35, 1365 (1976).